diff --git a/simgear/scene/material/mat.hxx b/simgear/scene/material/mat.hxx
index a939be4b..7115a8ef 100644
--- a/simgear/scene/material/mat.hxx
+++ b/simgear/scene/material/mat.hxx
@@ -36,7 +36,6 @@
 #include <vector>
 #include <map>
 
-#include <simgear/math/SGMath.hxx>
 #include "Effect.hxx"
 #include <simgear/scene/tgdb/SGTexturedTriangleBin.hxx>
 
diff --git a/simgear/scene/util/SGDebugDrawCallback.hxx b/simgear/scene/util/SGDebugDrawCallback.hxx
index 5818f641..4f02baaa 100644
--- a/simgear/scene/util/SGDebugDrawCallback.hxx
+++ b/simgear/scene/util/SGDebugDrawCallback.hxx
@@ -26,7 +26,6 @@
 #include <GL/gl.h>
 #include <osg/Drawable>
 #include <osg/State>
-#include <simgear/math/SGMath.hxx>
 
 struct SGDebugDrawCallback : public osg::Drawable::DrawCallback {
   virtual void drawImplementation(osg::State& state,
diff --git a/simgear/sound/sample_openal.hxx b/simgear/sound/sample_openal.hxx
index a231f663..a32b8719 100644
--- a/simgear/sound/sample_openal.hxx
+++ b/simgear/sound/sample_openal.hxx
@@ -41,7 +41,6 @@
 #include <simgear/debug/logstream.hxx>
 #include <simgear/structure/SGReferenced.hxx>
 #include <simgear/structure/SGSharedPtr.hxx>
-#include <simgear/math/SGMath.hxx>
 
 class SGPath;
 
diff --git a/simgear/sound/sample_queue.hxx b/simgear/sound/sample_queue.hxx
index 3d2c46a8..b2f96185 100644
--- a/simgear/sound/sample_queue.hxx
+++ b/simgear/sound/sample_queue.hxx
@@ -39,7 +39,6 @@
 #include <simgear/debug/logstream.hxx>
 #include <simgear/structure/SGReferenced.hxx>
 #include <simgear/structure/SGSharedPtr.hxx>
-#include <simgear/math/SGMath.hxx>
 
 #include "sample_openal.hxx"